So it there is a "window" open to the island, then why all the hoopla with recreating the first flight? Why the guitar and handcuffs and shoes and dead Locke in a coffin? If there is a window, don't you just go through it?
ELOISE: Aha. Here we go. [Sighs] All right. I apologize if this is confusing, but... [To Jack, who is distracted] Let's pay attention, yes? The room we're standing in was constructed years ago over a unique pocket of electromagnetic energy. That energy connects to similar pockets all over the world. The people who built this room, however, were only interested in one.
SUN: The Island.
ELOISE: Yes. The island. They'd gathered proof that it existed. They knew it was out there somewhere, but they just couldn't find it. Then a very clever fellow built this pendulum on the theoretical notion that they should stop looking for where the island was supposed to be and start looking for where it was going to be.
JACK: What do you mean, "Where it was going to be"?
ELOISE: Well, this fellow presumed, and correctly, as it turned out, that the Island was always moving. Why do you think you were never rescued? Now while the movements of the Island seem random, this man and his team created a series of equations which tell us, with a high degree of probability, where it is going to be at a certain point... in time. Windows, as it were, that while open, provide a route back. Unfortunately, these windows don't stay open for very long. Yours closes... in 36 hours.
DESMOND: Um, I'm sorry. Excuse me. [Chuckles] Am I really hearing this? That's what this is about? You're all going back to the Island willingly?
SUN: Yes. Why are you here, Desmond?
DESMOND: [Sighs, scoffs] I came here to deliver a message. Daniel Faraday--your son--sent me here. He wanted me to tell you that he and all the people on the Island need your help. He said that only you could help them. He didn't say Jack. He didn't say Sun. He didn't say Ben. He said you.
ELOISE: But I am helping, dear.
DESMOND: [Scoffs] Consider the message delivered.
ELOISE: I'm sorry to have to tell you this, Desmond, but the Island isn't done with you yet.
DESMOND: [To Jack] This woman cost me four years of my life--four years that I'll never get back because you told me that I was supposed to go to the Island! That it was my bloody purpose! You listen to me, brother, and you listen carefully. [Panting] These people--they're just usin' us. They're playing some kind of game, and we are just the pieces. [Lowers voice] Whatever she tells you to do... ignore it. [Normal voice] You say the Island's not done with me? Well, I'm done with the Island.
[Pendulum continues whooshing]
ELOISE: Jack... the binder in your hands shows all the air routes that fly over the coordinates where I believe the Island will be in little more than a day from now. There's a commercial airliner flying from L.A. to Guam. It's going to go right through our window. Ajira Airways, Flight 316. If you have any hope of the Island bringing you back, it must be that plane. You all need to be on it. It must be that flight. [Sighs] If you... want to return, you need to recreate as best you can the circumstances that brought you there in the first place. That means as many of the same people as you are able to bring with you.
JACK: And what if we can't get anyone else to come with us? What if we're it?
ELOISE: All I can tell you is the result would be... unpredictable.
JACK: So that's it? We just get on that flight, and we just hope that it works? That's all?
ELOISE: No, that's not all, Jack... at least, not for you.
And then the kicker when she talks to Jack, and only Jack:It is ridiculous of course. And I HOPE Eloise Hawking did not tell him the truth about why they need to recreate the conditions of the first flight. I hope there is some other reason for certain objects to be going back to the island. Because really, this "recreating" stuff is really getting on my nerves. It really seems idiotic. Hopefully it's a ruse of some kind. Please!
JACK: [Sighs] Why would he kill himself?
ELOISE: Ohh... there are many reasons, I'm sure, but the only one that matters is this--he is going to help you get back. John is going to be a proxy. A substitute.
JACK: A substitute for who?
ELOISE: Jack... who do you think? You need to, as best you can, recreate the conditions of the original flight... which is why you need to give John something of your father's. You have to get something that belonged to your father, and you need to give it to John.
ELOISE: That's what you have to do.
JACK: My father... is gone. My father has been dead for three years. You want me to... [scoffs] a--and to give it to Locke?! He's in a coffin! This is ridiculous.
ELOISE: Oh, stop thinking how ridiculous it is and start asking yourself whether or not you believe it's going to work. That's why it's called a leap of faith, Jack.
Like Locke's torn note says: I wish... I wish Hawking to be full of it.